Apparatus for automatic drilling and tapping of headed workpieces



July 14, 1959 J. w. BATCHELDER APPARATUS FOR AUTOMATIC DRILLING AND TAPPING OF HEADED WORKPIECES 6 Sheets-Sheet 1 Filed July 24, 1957 w m .L.\ M BMW Km m 1 M 66 WW .IlUl fl ATTORNEYS July 14, 1959 J. w. BATCHELDER 2,894,420

APPARATUS FOR AUTOMATIC DRILLING AND TAPPING OF HEADED WORKPIECES Filed July 24, 1957 6 Sheets-Sheet 2 INVENTOR.

JAMES W BATCHELDER BY $01M 5 $001M;

ATTORNEYS J. W. BATCHELDER APPARATUS FOR AUTOMATIC DRILLING AND TAPPING OF BEADED WORKPIECES July 14, 1959 6 Sheets-Sheet 3 Filed July 24, 1957 INVENTOR. JAMES W BATCHELDER BY $001M $901M ATTORNEYS J ly 1959 J. w. BATCHELDER 2,894,420

APPARATUS. UTOMATIC DRILLING AND TAPPI HEADED WORKPIECES Filed July 24, 1957 v 6 Sheets-Sheet 4 JAMES W BATCHELDER BY flol/zd $004121 ATTORNEYS July 14, 1959 J. w. BATCHELDER APPARATUS FOR AUTOMATIC DRILLING AND TAPPING OF HEADED WORKPIECES 6 Sheets-Sheet 5 Filed July 24, 1957 .Dn M R OL/\ 2 m m I E /fl Wm w m 8. I Wl fl S 0 MD A Y B 0 3 I, 5 I M my ATTORNEYS July 14, 1959 Filed July 24, 1957 Fig. I4

- J. w. BATCHELDER APPARATUS FOR AUTOMATIC DRILLING AND TAPPING OF HEADED WORKPIECES 6 Sheets-Sheet 6 I A! 41 H 20/ 215* INVENTOR. JAMES W BATCHELDER BY Lia fli k ial/ukk ATTORNEYS United States Patent i APPARATUS FOR AUTOMATIC DRILLING AND TAPPING OF HEADED WORKPIECES James W. Batchelder, Ascutuey, Vt.

Application July 24, 1957, Serial No. 673,878

14 Claims. (Cl. 77-5) The present invention generally is concerned with apparatus for automatically drilling or tapping a succession of work-pieces, and more particularly to the work head, that is the combination of functional assemblies and elements whereby headed blanks or work-pieces are fed successively to and clamped in a defined work station, presenting individual oriented blanks to tool means of such apparatus for performing an operation on the blank such as drilling, tapping or the like.

In my co-pending application, Serial No. 532,855 filed September 7, 1955, now patent No. 2,811,876, of which this application is a continuation-in-part, there is disclosed a complete machine for automatically drilling or tapping work-pieces fed successively to a work station before a a rotating tool. There the work station is defined by a cooperating pair of fixed and movable jaws holding the blank,'with axis disposed horizontally aligned with the axially fed rotating tool, by radially and axially applied sh ank and head clamping forces; the blanks are delivered, from a bulk loaded device, with heads engaged in feed track means and with axes horizontal to a position above the jaws to be injected into the jaws by an injection finger reciprocated past the track outlet to function also as an escapement device. A pneumatic actuating system for the work head and for advancing and retracting the tool, and electric control circuitry for coordinating the work head and tool actions in cooperating timed relation as required for continuous automatic openation, are also disclosed.

The work head of the prior application is excellently adapted to the handling of short or medium length shank work-pieces, but with relatively long shank blanks certain disadvantages appear. Since the feed tracks to the escapement orient the blanks with heads engaged between rails and with shanks horizontal, long shank blanks tend to interfere with each other on the track, particularly at the discharge or escapement point, where the tendency of adjacent blank shanks to cross would at times permit a part of a second blank to come under the injector blade, interfering with proper escapement operation and presentation of blanks at the work station.

The present invention is concerned with improvement of apparatus of such type. A primary object of the invention is to obviate such difiiculties, specifically by the provision of an escapement device accepting blanks from a feed track wherein long shank blanks are serially arrayed suspended by the heads with shanks between spaced track rails, the escapement'device inone operation orienting a blank with axis horizontal and simultaneously presenting it to the jaws for injection by a reciprocating injector blade or finger. Thus the injection and escapement function resides in spatially and structurally distinct mechanisms. v

Another object is the provision of a work head adapted to handle blanks from short to quite long shank lengths and of dilferent diameters, conducing to great flexibility of application. This end is attained primarily by the further provision of a set cooperating clamping jaws having faces adapted in the environment of use to engage a blank radially in self-centering or locating fashion at the work station defined thereby and having a plurality of head supporting reaction surfaces selectively used for different shank lengths; and by provision of readily adjusted components in the jaw mounting, the clamping, the injector and the escapement devices.

A further object is the provision of an apparatus wherein adjustment of the several functional components in changing from one blank size to another is minimized and simplified. A still further object is the provision of means for effectively segregating chips produced in the work operation from the work-pieces not only for the purpose of yielding a clean run of product but also to avoid chip interference in the working and clamping area. Another object is the utilization of acoolant stream generally required for the work operations as a means for maintaining proper orientations of work-pieces particularly of head-heavy short shank sizes;

Other objects and advantages of the invention will appear from the following description and the drawings wherein:

Fig. 1 shows the work head section of an apparatus embodying the present invention in generally longitudinal but irregularly taken sections, viewed from the operator's station or front of the machine;

Fig. 2 is an end elevational view of the work head with certain minor elements omitted;

Fig. 3 is a partial rear View corresponding to Fig. 2 with certain elements broken away or removed for clarity of representation of certain other structure;

Fig. 4 is a sectional detail taken at the line 4--4 of Fig. l;

Fig. 5 is a sectional detail of another part of the axial clamp assembly, taken at the line 5-5 in Fig. 1;

Fig. 6 is an end elevational detail view of a jaw carrier or vise frame assembly, with certain parts of other assemblies of the apparatus there indicated in fragmentary form to show the normal relation of parts relative to the jaws; v

Fig. 7 is an elevational detail of the clamping or working face of a fixed jaw with certain other elements superimposed thereon in dashed outline to show the working relation thereof relative to the jaws; I

Fig. 8 is a detail elevational view of an injector finger;

Fig. 9 is a detail view of a bottom stationary sector plate of the transfer and escapement assembly and certain other elements carried thereby;

Fig. 10 is a plan detail view of a transfer blade of the transfer mechanism;

Fig. 11 is an outline edgewise view of the upper end of the escapement and transfer elements indicating the relation of blanks to surrounding elements;

Fig. 12 is a perspective detailed view of a work-pieceguide element at the discharge end of the transfer and escapement assembly;

Fig. 13 is a schematic diagram of a pneumatic system for this apparatus; and

Fig. 14 is a wiring diagram for automatic controls.

In the drawings, the present invention is shown in a work head form adapted for use in a drilling or tapping machine of the general character of that disclosed in the aforementioned US. Patent 2,811,876, of which there is shown in fragmentary form a supporting bed B and a power driven rotary tool assembly D. In the manner set forth in the said application and hereinafter set forth for the instant work head W, the tool assembly D and the work head are independently mounted on the bed for sliding adjustment lengthwise of the bed toward and away from each other in the direction of the axis of tool Patented July 14, 1959.

retracted along its axis of rotation relative to a work-piece clamping station and carrying a drill chuck 11 as shown, or tap chuck or automatic reverse and back out tapping head, all as set forth in said application. Hereinafter, the apparatus will be discussed in terms of long shank rivets as work pieces to be drilled; and the right end of the work head and left end of the tool assembly D, as seen in Fig. 1, will be herein the respective front sides for convenience in describing the same, although with respect to the machine as a whole, Fig. 1 is oriented as seen from the front or operators station.

General organization In the work head (see Fig. 1), the primary functional assemblies, indicated by letters as general reference characters and hereinafter described in detail, are a workpiece clamping jaw carrier or vise V, located between a chip shield-drill guide S and a housing H, mounted and secured on the bed top surface in a manner permitting slidable adjustment lengthwise of the bed with respect to each other and the tool assembly; a pneumatically actuated work piece injection mechanism E for injecting a work-piece in a vertical direction down into a work station defined in the vise, supported by a base F as a forward housing wall mounted for limited adjustment in a vertical plane transverse of the bed on the front of the housing; a pneumatically powered work-piece axial head clamp A also carried on the base F; and a work-piece escapement and transfer mechanism T (omitted in Fig. 1, see Figs. 2 and 3) receiving work-pieces from a hopper feeder machine (not shown) in soldiered serial array along an inclined track R in a vertical plane and transferring individual work-pieces from the track to a horizontal axial dispostion at the top of the vise V in position for vertical downward injection into the vise by injector mechanism E.

Housing H The housing H includes a heavy flat bottom plate 20, a pair of parallel vertical flat bar or post elements 21 secured near its front end corners and joined by a top cross bar 22; plates 23, 24 shaped to form opposite hous ing side panels and curved into surfaces extending toward each other as a housing top wall; toward the rear, a vertical'flat post 25 extending in from the side panel of plate 23; and a top-hinged cover 26 for the rear of the housing. The several bar or post elements, the bottom member and plate members preferably are welded together, to provide a rigid housing.

A rectangular guide bar 28 fitted in a shallow groove extending throughout the length of the bottom surface of bottom member 20 and secured by cap screws 29 is received as a slide element between guide surfaces of a T- slot 31 cut the entire length of the bed B. Clamping blocks 32, into which are threaded corresponding clamp bolts 33 extending through aligned unthreaded apertures in bottom plate 20 and bar 28, are drawn upward into clamping relation against shoulders 31a of the T-slot, by captive box wrenches 34 extending from openings at the rear of the housing and in side panel 24. The wrenches are retained in position about the heads of bolts 33 by a common retainer bar 35 secured to and spaced from the bottom plate of the housing by cap screws 36 and'interposed corresponding spacer sleeves. An adjusting screw 38 journalled in a bracket structure 39 on the bed, and provided with a lock nut 40, is threaded through the housing'rear post 25 as means for fine position adjustment of the housing on the bed.

The base F, which may be a casting with milled coplanar back surfaces bearing on corresponding flats of the housing bars 21, 22, is secured as a housing front wall or cover, by four corner bolts extending through washers and oversized holes in the casting and threaded into the bars 21,22, whereby a limited degree of horizontal adjustment of the base is possible in a vertical plane transverse to the bed.

A pneumatic cylinder 42 with spring retracted piston is mounted between angle brackets bolted 'on top of the housing for actuation of the rivet injector mechanism E; and another pneumatic cylinder 44 with spring returned piston, for the axial rivet head clamp A is axially adjustably supported, parallel to 42 with axes in common vertical plane, by two right angle bracket members 45 of a slide structure in a slideway 46 secured on and spaced from the inner side wall of plate 23. An adjusting screw 47 journalled in and reacting on post 25 is threaded into the slide for moving the cylinder unit 44- along its axis, the screw having a suitable lock nut thereon.

Injector mechanism E On the flat forward vertical face 50 of a hollow projection of the base member F, an injector slide number 51 is mounted for vertical reciprocation in a slideway 52 provided by two like spaced parallel elongated plates 52a, 52b bolted to F, slide member 51 being in the form of a right angle element with the bottom region of the forwardly projecting vertical leg 51a relieved (on the right side face as viewed in Fig. 2) to form a seat with vertical guide edge into which is fitted and bolted the upper squared end of an injector blade or finger 53; the other leg 51]) of the slide member being retained between the slide plates and guided by disposition of the slideway plate 52a in a broad shallow flat slot formed between slide leg 51a and a parallel vertical flange on 51b. The specific form of the injector finger, for which various widths are used for different rivet lengths (one size appearing in Fig. 8), is later described with reference to the work clamping jaws in vise assembly V.

Through a bell crank 54 pivotally mounted on the top of base F, and a link 55 with opposite ends pivotally connected to the slide 51 and long arm of the bell crank, the motion of the piston 42a of cylinder unit 42 hearing on the roller 56 on the short arm of the bell crank is applied to the slide 51 for a downward injection stroke to carry a rivet into the vise V; while the biasing force of a helical compression spring 57, located in a bore in base F to bear on a collared rod 58 with end pivotally connected to the bell crank, is in like manner applied for the return stroke of the slide 51 to its retracted uppermost inactive position.

Mounted within the back recess of the mentioned projection of base F are a microswitch 60 and a lever 61 disposed therebeneath having a short arm engageable with a spring returned actuating button on the switch bottom and a roller carried on the long lever arm located for engagement by a pusher rod 62, slidable in a vertical bore of the base. On the injection stroke the rod is depressed by contact of an adjustable bell crank stop screw 64 with the dowel 65 in a counterbore above the push rod, the bushing 66 in the bottom of the counter bore serving as a stop for the downward movement of the dowel.

Axial hea a clamp assembly The axial head clamp system, best seen in Fig. 1, actually involves the aforementioned pneumatic cylinder 44; the axial clamp assembly A next described for applying axial force to the rivet head; and, supporting the underside of the head, reaction surfaces provided on clamping jaws later described in the vise assembly V. The axial clamp assembly A includes a shaft 69 aligned with the piston member 44a and axially reciprocably supported by 'a flanged bushing 70 in and bolted to base F, a keeper guide plate 71 (appearing in Fig. 4) bolted to one side of sleeve 70 hearing on a lengthwise flat of 69 to hold the latter from rotation; a preloaded retracting compression spring 72 interposed between the back end of bushing 70 and a snap-ring 73 in a grooved end of 69; and a forwardly extending axial clamp finger or plate 74 bolted onto the cut-away end of 69 forward of base member F. The axial head clamp plate 74, with majorflat portion disposed generally in a vertical axial plane of shaft 69 beneath the forwardly projecting portion of base F, has a vertical back edge located by a flat surface 69a on the shaft, and top and bottom margins 74a, 74b bent to one side at an angle of 45 for the top (as seen in Fig. 5), the bottom bend serving to stiffen the same against deflection by clamping force applied to a rivet head at a front edge of the plate.

Thus as the spring 72 is prestressed to urge 69 in following contact with piston 44a into the retracted position of the latter, adjustment of position of cylinder unit 44 by screw 47 serves to determine the retracted or fully released position of the forward rivet engaging edge of clamp plate 74.

Vise assembly The relation of the vise assembly to other assemblies is best seen in Figs. 1 and 2; and its structure, in the front elevational view of Fig. 6 and in Fig. l. A rigid vise frame 76, having front and rear walls 76a, 76b connected (at the right in Fig. 6) by a narrow top wall 760 and at the left by a side wall 76d, supports a fixed rive-t clamping jaw block 78 on a jaw seat formation 76; and also a movable jaw block 79 in a seat 806 formed in the upper end of an arm 80 pivotally supported between the front and rear frame walls on a pivot shaft 81 extending through the end of the lower oblique arm portion. The pivot shaft axis lies generally in a vertical plane including the path of movement of the injector finger 53 and the intended position of the axis of a rivet held between the jaws. An oblique rivet discharge chute 76f extends from the region under the movable jaw seat portion of the arm 80 downwardly through the right open end of the vise frame, as viewed in Fig. 6, to direct finished work dropped out of the jaws to a receptacle at the back of the machine.

The vise frame 76, which may be a casting providing the named elements 76 a--;, has bolted along its lower front edge an anchor and guide plate 820: slotted for clamp bolts 82c whereby the guide plate, and hence vise frame, its rigidly but transversely adjustably secured to the front edge of plate 82; the entire assembly being slidable on the bed for adjustment and clamping in position by means of a guide bar 83 engaged in the bed slot 31, a clamping block 84 and clamping bolt (for which a transverse slot is provided in the vise bottom), and captive wrench 85 arranged generally as described for the housing H. A fine adjustment screw 87 threaded through the walls 76a, 11 of the frame bears on the end of an aligned stop rod 88 (see Figs. 1 and 3) carried by the base F, but described here for convenience. The rod 88, slideable in a corresponding bore through base F over a range permitted by retainer snap rings in opposite end grooves, has a series of spaced circumferential grooves, selectively engaged by the bifurcated end of a spring biased lock plate 89 slideable in a guide mounting 90 on the front of base F to hold the stop rod against axial movement, and retractable to change the stop rod setting. With the vise frame unclamped and moved to bring screw 87 to bear again on the stop rod, the fine position adjustment may be made with 87 before reclamping the frame.

A radial clamping pneumatic cylinder unit 92 (see Fig. 2) with spring retracted piston is supported on the left side of the vise frame by a bracket, the piston rod of which carries an adjustable jaw contact element 93 threaded thereon with reduced end extending through a recess 80a in the jaw arm to bear directly on the movable jaw 79. A bracket plate 94 (see Figs. 1 and 6) bolted on the top edge of frame back wall 76b, supports a movable jaw biasing device including a pair of plates 95, 96, a threaded rod 97, a biasing spring 98 interposed on the rod between a nut and plate 95 at the left and a nut bearing directly on plate 96 at the right. A short lug or finger 99 depending from a spacer block 100 secured on the upper left side of the movablejaw is 6 engaged in the space'between the top edges of plates 95, 96; When a rivet is injected downward between the jaws as hereinafter detailed, thereby forcing the movable away from the fixed jaw, the finger 99 bearing upon the upper end of 95 pivots the latter as shown in Fig. 6 about its bottom edge on bracket 94 against the bias spring and an initial light force is developed radially of the rivet to hold it between the jaws; while plate 96 serves as a stop for inward movement of the movable jaw even by chance after plate 95 has stopped flat on the bracket, when no rivet is at hand.

From the end elevation of the jaws 78, 79 appearing in Fig. 6 it is seen that both jaws have a bottom and side face at right angles to each other bearing on corresponding surfaces in opposed jaw seats formed on the top portion 76c of the frame and the movable jaw. The jaws are secured by cap screws extending through the vertical walls of the seats into corresponding threaded apertures of the jaws, while cap screws threaded endwise into the jaw seat regions with heads overhanging the front ends of the jaw support the latter endwise. On the lower half of the inner or working face of the movable jaw there is a longitudinal horizontal V-notch 79a cooperating with the opposed flat portion of the fixed jaw to define a rivet clamping or work station. Below the V-notch level, both jaw faces are straight to form a very short throat and then equally beveled or divergent to the bottoms at 78b, 79b. Above the V-notch level, the opposed jaw faces are generally straight and approximately parallel until near the top the movable jaw is beveled at 790 to about 15, the same angle as its bottom level, and at a still higher level a 45 bevel 780 of the fixed jaw is encountered. The bevel 78a on the fixed jaw is for accommodation of transfer mechanism.

The inlet bevels 78c, 79c at the top of the jaws receive a rivet from the transfer mechanism and locate the same in the path of the injector finger; and further as the injector carries a rivet downward, from the locus of initial contact with the inlet bevels, the bevel 79c assumes the principal function of a camming surface causing the movable jaw to spread against the force of spring 98. This of course permits the release of a preceding rivet, which quickly drops clear of the jaws into the rivet discharge chute, and as the incoming rivet reaches the V-notch at the end of the injector stroke, the bias spring 98 returning the movable jaw and the shape of the V- notch causes the rivet to center itself in proper location, due to the three point contact" on the two sides of the V and on the fixed jaw flat. This also permits a range of shank diameters to behandled by one set of jaws. By use of the disclosed cooperating jaw faces only one seat formation is required to be machined, the V-groove of the movable jaw, and there is no necessity of matching seat formations on the jaws of a set, facilitating and lowering cost of jaw fabrication. Also with the camming taking place only at the movable jaw, possibility of the rivet slipping off to one side or the other of the injection finger, with the finger in consequence sliding by the rivet and thereby failing to inject the same, is minimized. The short throat and divergent outlet bevels ensure quick clearance of finished work and avoid interference with the incoming rivet.

In detail Fig. 7, an elevational view of the fixed jaw working or clamping face, a series of spaced parallel vertical slots are indicated at 78d, and by dashed outline the positions of the heads and shanks of five different sized rivets are indicated in clamped position relative to the jaw. The cooperating movable jaw is not shown since an opposed series of slots of like spacing are there present. It will be noted that the undersides of the heads are supported axially by the shoulders provided at five different locations by the left end of the jaw block and the right side walls of the successive slots, when axial clamping force is applied to a rivet head by the axial clamp blade or finger 74 also indicated in fragmentary form in dashed outline in position relative to the jaws for clamping a rivet P with head engaged in the first pair of op posed slots from the left. At 78 inward of each of such shoulders, a slight vertical bevel is formed to accommodate the flare or swelling of a rivet shank caused under the head by cold heading. For a given set of a movable and .a fixed jaw intended to handle a certain range of rivet sizes, the widths, spacings and bevels of corresponding opposed slots are identical, but the depths of the correspondingmovable jaw slots are greater in consequence of the shank reception in the V-notch. However, within each series, the slot widths and depths vary as required to accommodate and clamp rivets of different shank lengths and heads sizes with the end of the shank to be drilled in each case presented at substantially the same place at theforward end of the jaws.

Before further explanation of structure, certain relations of the material thus far described are here summarized. The work station defined by the movable jaw V-notch and the flat face of the fixed jaw is located so that a rivet clamped therein has its axis aligned with the axis of tool rotation, parallel to the bed T-slot. The radial clamp cylinder 92 applies force to the forward part of the movable jaw at the level of the V-notch for application of a radial clamping force to the work near the shank end being drilled or tapped; and the axial clamp finger 74 is aligned with the tool axis. The jaw vise is located below the injector finger 53, so that the fixed jaw clamping face is parallel to the plane of reciprocation of the injector between the jaws, which in turn passes through the axis of tool rotation, therefore of the rivet in the work station.

Now with a given set of jaws, the entire jaw vise may be set back under the overhang of the forward projection of the frame by use of the adjusting and stop means previously described to successive different positions (five, for the four slotted jaw form indicated by Fig. 7), corresponding to a series of successively shorter shank lengths, to bring the rivet head supporting shoulders of the jaws into identical position under the back edge of the injector finger. The spacing of the grooves in stop rod '88 is selected therefore to correspond to the jaw slot spacing. Accordingly the span or width of the injector finger, which should equal at least two-thirds of the rivet shank length, is decreased for successively shorter rivets. In Fig. 8 there is shown a side elevation of an injector finger 53 intended for handling rivets of the greatest length to be accommodated in a jaw set corresponding to the fixed jaw of Fig. 7. The face of the finger to be disposed adjacent the movable jaw has milled therein a series of relatively broad and shallow grooves 53a to accommodate and clear the ribs formed between the movable jaw slots; the vertical lands 53c of the injector, formed between such grooves and permitted to enter the jaw slots, contributing to the stiffness and rigidity of the blade. The dashed outline 53, in Fig. 7, of a smaller injector blade than that of Fig. 8, superimposed on the fixed jaw indicates the relation of the movable jaw slots to the injector finger ribs, since the slot spacing of fixed and movable jaws is identical. Since setting the vise assembly back under the injector for shorter rivets would result in projection of the front of a large blade (such as that of Fig. 8), beyond the jaws, While clearance with other elements of the apparatus is required, a series of successively narrow blades is provided, all of which however preferably have the same height, a similar top slot 53b for the bolt securing the finger to the injector slide 51, and squared top back corner for locating in the slide seat.

Chip shield assembly An L. bracket 110, .slideably supported on the bed and clamped thereto by a guide bar, clamping block and captive wrench arrangement similar to that previously described for housing and vise, carries a chip cone 111 aflixed to the top rear side. The .apexregion of the cone directed toward the .jaws has a rather large central aper ture for the drill extending therethrough toward the work. A chip chute 112 inclined downward to the right of Fig. 2 and removably supported by a spring clip 112a hooked over the top of the L bracket 110, partially embraces and projects forwardly from the rim of the chip cone. On the rear of the cone (see particularly Fig. 3) a vertical rib 111a is formed with a fiat back face providing a 'seat for a bushing disk 113 secured thereon by overhanging bolted clamp plates 114. The central aperture of the disk is normally oversized relative to the drill with which used, but can fit the drill to serve as a drill guide bushing. The bushing is counterbored to carry a conical interior surface from the chip cone down to the work region.

An adjusting screw 1'16, threaded through the L bracket to bear upon the front of the vise assembly, facilitates close adjustment of the chip cone and bushing relative to the work station.

Transfer and escapement mechanism The transfer mechanism T (omitted in Fig. 1 for clarity, but seen in front elevation in Fig. 2 and in side elevation with certain parts removed in Fig. 3) includes a vertical base plate mounted at the right of the vise assembly (as viewed in Fig. 2) in front of, in spaced relation to, and independently of the base F by bolts 121 passed through spacer sleeves 122 and threaded into the housing posts 21 and cross member 22, oversized apertures in the base F clearing the spacer sleeves to allow some shift of the base F. A pneumatic transfer actuating cylinder unit 124, of the spring returned piston type, is supported by a bracket 125 affixed to base plate 129 and extending laterally of its right side edge. A lower stationary sector plate 127 (see detailFig. 9') is supported on the base 120 by an underlying angle bracket 128 in a plane inclined at 45 to the plane of injector finger reciprocation and with its upper end edge 127a terminating parallel to and slightly beyond the inlet bevel 780 of the fixed jaw, while an upper stationary sector plate 129 is held in spaced parallel relation to the lower plate by a bracket 144a on the outer face of a member of track R, later detailed. The shape of the plate 129 is similar to the underlying part of 127.

A rocker shaft 131, with axis perpendicular to the sector plate plane and journalled in a tube 132 supported by an angle bracket 133 on base 120, at its lower end carries a transfer blade to be swung in parallel fashion between the sector plates 127, 129, by the force of the cylinder unit 124 acting upon the rocker arm 134 clamped on the top end of the shaft. The rocker arm includes a roller 134a upon which bears the contact head 124a adjustably threaded onto the end of the piston rod in unit 124; and toward the opposite end of the arm there is pivotally connected one end of a spring guide rod 135 having its other end movable through a washer and oversize aperture in bracket plate 125. A preloaded transfer blade return spring 137 interposed between the rod pivot structure and the washer is supported on the rod 136.

The general form of the transfer blade 130, seen best at its retracted position in Fig. 3 where certain guide elements of the assembly are omitted, provides a straight edge 138a for-engaging the length of a rivet shank and terminating at a notch 13% at the inner arcuate edges 127b, 12%, of the sector plates to receive the head of a rivet. It may also be seen from Fig. 3, that upon clockwise rotation of the transfer blade through about 90", a rivet P initially on the sector plate and engaged by the blades as indicated by the dashed outline, will be transferred to a position above the jaws and at the same time changed in orientation to a position with axis horizontal and shank pointing toward the tool assembly.

The transfer blade includes a hub 13% slotted at right angles to the direction or" edge 130a and including sur- 9 faces slideably fitted onto a corresponding head formation 131a on the bottom of the rocker shaft and clamped thereon by a screw 139 extended through one side of the hub, a radially elongated aperture in the shaft head, and threaded into the opposite side of the hub. This permits change of position of the blade edge 130a (relative to the line of rivet discharge of a feed track later described) as required for shanks of different diameters.

Also carried on the top of transfer blade 130 in the hub region (omitted in Figs. 2 and 3; seeFig. is a thin fiat rivet head guide 140, adjustable toward and away from the rocker shaft axis for different rivet head heights, which holds the heads of rivets being transferred against the inner arcuate edges of the transfer sector plates.

In Fig. 11 there appears in schematic form a top edge- Wise view of the stationary sector plates 127, 129, the transfer blade 130, the adjacent ends of rigidly spaced parallel members 144, 145 forming the basic structure of the inclined track R, down which rivets or other headed blanks or work pieces are fed with heads bearing on the top surfaces of and shanks suspended between members 144, 145. The track structure as such, and also various bulk loaded feeders used therewith, are well known to the art; and so are here no further detailed except to note that for handling work piece shanks of different diameters, the members 144, 145, though rigidly supported relative to the transfer mechanism components already described, are simultaneously adjustable toward and away from the lower stationary sector plate 127, upper sector 129 being therefore adjusted with 144 in its parallel spaced relation to 127, and also that member 144 is fixed and 145 movable as far as transverse adjustment is concerned.

The first rivet in coming off the end of the track encounters the lower sector plate 127 at the position P-1, and there is arrested with its head overhanging the inner arcuate edges 127b, 1291: of lower and upper sector, the right edge of the latter being a continuation of member 144; the shoulder of notch 1301) in the transfer blade; and the end of track member 145. The head of the rivet is also located below the arcuate head guide 140 on the transfer blade, not shown in Fig. 11.

A thin spring plate 148 (appearing only in Figs. 9 and 11), formed of spring strip folded upon itself and slipped over the left side of the lower sector and the guide plate 149 therebeneath, lies flat on the top surface of plate 127 with its straight edge 148a forming a slight shoulder in spaced parallel relation to the beveled edge 13001 of transfer blade 130 at its retracted position, between which the shank of a rivet at the bottom of the track is received and held, thereby holding a following rivet in the track. The spring plate 148 is slotted for screws 150 securing the plates 149 and 148 on the lower sector, to permit some adjustment of position of the edge 148a relative to the retracted transfer blade position as required for dilferent shank diameters.

It will be noted that when the transfer blade swings clockwise to transfer a rivet from the bottom of the track to a position above the jaws as previously described, the blade effectively closes off the outlet of the track until it has returned to retracted position, whereupon the next rivet is permitted to escape from the track into the position P-l in readiness for the next transfer stroke or swing of the blade. Thus the transfer mechanism, considered as including the lower end of the track, serves also as an escapement mechanism presenting blanks singly to the top of the rivet jaws.

To guide and direct the transferred rivet from the top or discharge edges 127a, 129a of the sector plates to a position resting beneath the injector finger 53 in the trough or groove formed between the inlet bevels 73c, 790 of the jaws, a rivet ejector spring element 152 and guide spring element 153 are mounted on the top of upper sector plate 129 (see Figs. 2 and 6). Both elements are 10 plate in such manner that they may be adjusted in position in a direction perpendicular to the discharge edge of and parallel to the sector plate 129.

The guide spring element 153 (see also detail Fig. 12) curves into the elongated flat guide surface 153a spaced outwardly beyond and parallel to the sector discharge edges 127a, 129a, and terminating adjacent the side of injector finger 53, to define a rivet ejection path past the edge 127a into the space between the jaw inlet bevels and beneath the injector finger. An inward slot 153b, parallel to and near the rear edge is provided in the guide surface 153a in order that a coolant conduit nozzle 156a may direct coolant downwardly therethrough perpendicularly on the shanks of head-heavy, short-shank blanks to keep them horizontal while awaiting injection on the jaw inlet bevels. Where this is not required to prevent cocking of the rivets the coolant nozzle may be aimed at the end being drilled.

The ejector spring 152 bent obliquely along its upper margin to form a lip 152a projecting outwardly and downwardly beyond the upper sector edge 129a into the path of a rivet, is displaced outwardly and upwardly by an emerging rivet moved by blade 130, and serves therefore to eject the rivet downwardly to the jaws through the defined ejection path as soon as the rivet is pushed by the blade beyond the discharge edge 127a. The head of a rivet lies beyond the rear edges of guide surface 153a and lip 152a while the shank passes between 153a and edge 127a.

It may be here noted also that the bent top margin of the axial clamp blade 74, in extending parallel to and in spaced relation to plane of the jaw inlet bevel 78c, serves in cooperation with the shoulder surface of the jaw slot utilized for axial clamping, to confine the axial position of the rivet head in transiting to a position beneath the injector finger 53 in readiness for a downward injection stroke of the finger to carry the blank into the work seat. Considering Fig. 7, where not only is the working face elevation of the fixed jaw shown in solid lines, but also in dashed outline the forward end of the axial clamp blade 74 (at an exaggerated retracted position against the rivet head P-2) and the lower portion of an injector finger 53 corresponding in size to the rivet engaged, it is seen that the upper portion 74c of the front edge of the axial clamp slopes downwardly toward the head engaging portion, to serve as a camming surface advancing the rivet head forward toward engagement with the shoulders of the jaws as the finger 53 carries the rivet downward.

Other components of the work head The aforementioned nozzle 156a may be a flexible or adjustable tube attached to the discharge conduit 156 spaced from and secured to the base F as shown in Fig. 2, though partially broken away. The coolant system, including an electric motor and pump supplying the coolant to the conduit 156 and a tray below the bed gathering the used coolant and returning the same to a reservoir, is advantageously that specifically described in the aforemention application, but is here no further detailed, except to note that the nozzle is adjustable to direct the discharge stream either as previously described for holding short head-heavy rivets, or normally upon the part being drilled through the vertical slot between the jaws, whereby any small chips escaping from the chip cone are flushed downwardly clear of the jaws.

As seen in Fig. 13, a compressed air supply line 170'- formed from flat spring stock and secured to the sector provided with a strainer 171, shut-off valve 172 and oiler,

173 branches into five lines 174-478 through corresponding pressure regulators with gauges all designated 179. The branch 175 with poppet valve 189 constantly applies low pressure air to one end of a tool spindle traversing, double-acting pneumatic cylinder 181 for retracting the tool. Branch 174 supplies higher pressure air to the other end of 131 for tool feeding advanced against the low pressure through an air flow control valve 182 and a solenoidally operated three-way air valve 183 directing air to 181 when energized and exhausting the same to atmosphere when deenergized to permit quick tool retraction; the valve 318i) permitting displacement of air on the low pressure side on tool advance.

Branch 1'76 directs air through a solenoidal three-Way valve 185 and a quick exhaust or dump valve 186 to the axial clamp cylinder unit 44 for applying axial clamp force; the valve 186 being adapted for quick exhaust of the cylinder air to the atmosphere when air pressure is cut oil by deenergization of 185. Air is supplied by branch 177 to radical clamp cylinder 92 in similar fashion through a three-way solenoidal valve 187, quick exhaust or dump valve 188, with however an adjustable needle valve 1% inserted before 187 for controlling the air flow rate to the cylinder, to ensure that full radial clamping force will not be developed until the axial head clamp force is applied to the rivet.

Branch 178 supplies air through a common solenoidal three-way valve 189, such as those previously described, through sub-branches 178a, 17315 to the transfer actuating cylinder 12- and injector finger cylinder 42, each sub-branch including again air flow control valves El, 192 including adjustable needle valves controlling air flow to the cylinder which needle valves are by-passed by ball check passages permitting free exhaust flow from the cylinders.

Preferably the aforementioned dump valves are mounted very close to the corresponding cylinders to further rapid exhaust and quick action.

The circuitry diagram of Fig. 14 and manner of function is essentially identical to the pe tinent portion of the previous application, and the same is presented here only for convenience of reference. The solenoids of the aforementioned valves are designated by like numerals. Conventional power circuitry for the normally continuously running tool drive and coolant pump motors are omitted.

Limit microswitches 2% (normally closed), 2% (normally open) and 2&2 (normally closed) are respectively first and second retracted limit switches and a forward traverse limit switch, connected by suitable linkages to be actuated by the tool spindle in its axial motion, so that Ziltl and 231 are respectively closed and open at full tool retraction, 2% opening shortly after tool advance begins and 201 closing shortly thereafter, with a reverse sequence of actuation on the retraction stroke; and 262. being adjustable to open upon full advance of the spindle to a desired point of tool feed. Microswitch 6% is normally open to be closed upon injection of a blank into the jaws.

Lines 295, 206 are supplied with power from an external source and line 296 is connected first to a common connection of the retracted limit switches 2%, 291 and secondly (through a generally closed tool retraction manual safety switch 2%? hereinafter merely considered a part of line 2&6) to one side of the coil in relay 208, and one side of tool advance solenoid coil 183. The other side of coil 1% is shown connected through normally closed contacts of a second relay 210 to the second side of the coil and the movable contact in relay 2% and to one side of switch oil. However the relay Zltl and cycle timer 211, the output impulses of which open the contact in the former, are merely a convenience for causing oscillation of a drill in certain operations, and the valve solenoid 183 will be considered as permanently connected in the circuit.

A manual switch 212 connected in series with the forward traverse limit switch 202 between line 205 and the second or fixed contact of relay 268 is closed for automatic operation of the entire drilling and tapping machine; and another manual switch 213, between one side of the injector mechanism valve solenoid 189 and a common point of switches 202, 212, when closed permits operator controlled single cycle operation, and when open renders tool advance impossible. The other side of solenoid 189 is connected to the remaining side of switch 2 3%.

Line 2% is also connected to the remaining side of switch 60 and to the parallel connected radial and axial clamping valve solenoids 185, 187, the latter in turn bein connected to the remaining side of switch 201. Further a pair of simultaneously closed switches in a push-button unit 215 are also provided to connect the injector valve solenoid 189 directly to lines 205, 296 to actuate the injector slide mechanism when switches 212, 213 may both be open as in set-up operations.

Operation The operations of the individual assemblies have been explained as each was described. However in summary the overall operation of the work head of this invention is set forth in the environment of a machine with the described controls. Rivets are assumed to be in the track, and therefore a first blank is present before the retracted transfer blade 130, but none is present below the injector finger. In starting operation, switch 215 may be momentarily pressed, energizing solenoid valve $9 to actuate both cylinder 4-2 and 124, causing not only a fruitless injection stroke of finger 53, but also a transfer stroke of blade 13h to bring a rivet onto the jaw inlet bevels, without however initiating an advance and retraction cycle of the tool or clamping action. The circuit condition is then again as in Fig. 14. Then by closing switches 212 and 213, solenoid valve 189 is again energized, to cause another injection stroke whereby the first rivet is carried down into the jaws and a simultaneous transfer stroke brings up another rivet.

The downward stroke of the injector mechanism in closing microswitch 60 energizes and closes relay 2%, and also energizes the tool advance solenoid valve 183 to start advance of the tool thereby successively opening limit switch zoo and closing 261. Accordingly 189 is deener ized, and injector retraction follows, opening as, but tool advance solenoid 183 remains energized because relay 2% is self-holding until 202 is opened; and radial and axial clamping solenoid valves are energized and opened to cause actuation first of the axial and then of the radial clamping systems. The tool is then fed into the Work to the requisite depth, opening forward limit switch 202, to deenergize and open relay 208, deenergizing solenoid valve 183 to cause retraction of the tool, which in turn closes the forward limit switch 202 at the beginning of retraction, and near the end successively opens 201, then closes Zllt). Opening 201 deenergizes solenoid valves 185, 137 to release axial and radial clamping pressure, and closing Zllti starts another cycle by causing a transfer and injection stroke as before. Since Ztlft does not open until near the end of the tool retraction, the axial and radial clamping cylinders remain pressurized to hold the blank as required for backing out a tap when the machine is used with an automatically reversing and back-out tap holder.

It is obvious that in starting operations 212 and 213 could be immediately closed, which would merely cause an entire first cycle of operation without a blank in the Work station; and also that with 212 open and 213 closed, closing 215 to cause a full injection and transfer stroke, and keeping the same closed will keep relay 208 closed for tool advance to carry out one complete cycle 13 not only of work head functions but of entire machine operation, since the tool advance will continue until 202 is opened. j

It may be noted that with corresponding modifications of the jaw clamping structure, the blank injection, transfer and clamping mechanisms may be usefully applied also where work operations are to be carried outwith a tool advanced toward the blank in a direction other than axial.

I claim:

1. A work head for clamping individual elongated round shank work blanks at a work station for a work operation by a tool advanced along a horizontal path coincident with the clamped blank shank axis, comprising: a fixed jaw and spaced therefrom a movable jaw shiftable toward and away from the fixed jaw in a direction transverse to said path, said jaws defining therebetween said blank clamping or work station, and the movable jaw being yieldably biased toward the fixed jaw; a blank injection mechanism including an injector finger reciprocable from a retracted position outside and spaced from the jaws into a space between said jaws in an injection stroke for engaging a blank shank and translating the same in a direction perpendicular to the shank axis into the work station; and a blank escapement and transfer mechanism including inclined track means wherein headsuspended blanks are fed in a vertical plane in serial soldiered array in a plane perpendicular to said path, to a track outlet offset from said jaws, means adjacent the track outlet receiving a blank therefrom and holding the blank in a location closing the track outlet, means including a transfer blade angularly movable from a retraced position across the track outlet to close the same for engaging a blank and transferring the same with an angular change of blank axis orientation from said location to a position between the retracted position of said finger and said jaws, and means for returning the blade to retracted position to open the track outlet to permit a subsequent blank to enter said location.

2. Ina work head for clamping individual headed elongated shank Work blanks at a Work station for a work operation by a tool advanced along a predetermined path with respect to the clamped blank shank axis, and including blank clamping means defining said work station and having an inlet for a blank translated in a direction transverse to the blank axis, a blank escapement and transfer mechanism for presenting blanks individually at said inlet comprising: inclined track means wherein head-suspended blanks are fed in serial soldiered array in a vertical plane to a track outlet offset from said inlet, inclined first sector-plate means spaced endwise from the track outlet and disposed transversely of the track to engage a blank discharging therefrom at a location closing the track outlet, second sector plate means extending from one side of the track in spaced parallel relation to the first plate and defining therewith a blank shank passage terminating in proximity to said inlet, said plate means having 'arcuate edge portions substantially coextensive with said passage for supporting the underside of a blank head, a transfer blade mounted to swing about an axis perpendicular to the plane of the said first sector plate means, said blade extending generally radially of the last said axis and havingan edge adapted to engage the length of a blank in arcuately moving from a retracted position, across the track outlet .to close the same and into said passage, for engaging a blank and transferring the .same from said location to said inlet, and means for returning the blade to retracted position opening the track outlet to permit a subsequent blank to enter said location.

3. Mechanism as described in claim 2, having said passage terminating at a discharge opening defined by parallel edges of respective said plate means in proximate but spaced relation to said inlet, guide means carried by the second said plate means extending toward said inlet in spaced relation to the last said edges to define therewith a second blank passage at an angle to the first, and resilient blank ejector means disposed in said second passageway to be resiliently displaced by a blank forced from said discharge opening by said blade, whereby the blank is impelled in said second passage to said inlet. 4. Mechanism as described in claim 2 having an element mounted on and presenting on one of said plate means a slight blank shank engaging shoulder spaced from the retracted position of said edge of the transfer blade to hold a blank in said location closing the track outlet until transferred by said blade.

5. Mechanism as described in claim 2 wherein said transfer blade is supported for arcuate movement by means providing adjustment of the retracted blade position transversely of the track for accomodation of a range of blank shank sizes.

6. Mechanism as described in claim 2 wherein said transfer blade includes an element providing an abutment for limiting endwise movement of the blank relative to the blade during blank transfer movement.

7. Mechanism as described in claim 2 wherein said second plate means is adjustable toward and away from the first plate means and said track means is adjustable toward and away from the first said plate means and elements of the track are mutually adjustable for accommodation of a range of blank diameters.

8. A work head for axially and radially clamping individual headed elongated shank work blanks at a work station for a work operation by a tool advanced along a predetermined path with respect to the clamped blank shank axis, comprising: a housing; a jaw mounting frame secured in adjusted position relative to the housing; a fixed jaw on the frame, and a movable jaw spring biased toward the fixed jaw, and stop means for limiting the approach of the movable jaw to the fixed jaw to maintain a space therebetween; said jaws having the opposed faces shaped to include a fiat surface on the fixed jaw and a V-notch on the movable jaw providing three line contacts and defining said work station for blanks of a range of shank diameters and also to include respective inlet bevels forming a blank locating supporting trough as an entrance to the jaws; a blank injection mechanism mounted on said housing including an injector finger reciprocable from a retracted position outside of and spaced from the jaws into a space between said jaws in an injection stroke for engaging a blank shank on said inlet bevels andtranslating the same in a direction perpendicular to the shank axis into the work station; the inlet bevel on the movable jaw serving as a 'camming surface whereby injection of a blank shifts the movable jaw to release a preceding blank from said work station; said jaws' having a plurality of parallel paired respective slots extending in the direction of injector finger reciprocation across the opposed faces through said bevels, notch and flat face providing pairs of coplanar blank head axial clamping reaction surfaces, each pair of slots also providing blank head radial clearance upon blank injection and radial clamping whereby the said carnming of the movable jaw and radial clamping are effected on a blank shank; means on the jaw frame for applying positive radial clamping force to the movable jaw; means mounted on said housing for applying a positive axial head clamping force to a blank in said work station including a spring retracted head clamp element aligned with the space between said jaws; a blank escapement and transfer mechanism for presenting blanks individually at said inlet bevels including inclined track means wherein head-suspended blanks are fed in a vertical plane in serial soldiered array to a track outlet ofiset from said inlet bevels endwise and to one side thereof, inclined first sector plate means mounted on the housing transverse to said vertical plane and spaced endwise from the track outlet to engage a blank discharging therefrom at a location closing the track outlet, second sector plate means extending from one side of the track in spaced parallel relation tothe first plate means and defining therewith a blank shank passage having an outlet in proximity to the jaw entrance, said plate means having arcuate edge portions substantially coextensive with said passage for supporting the underside of a blank head, a transfer blade mounted to swing about an axis perpendicular to the plane of the said first sector plate means, said blade extending generally radially of the last said axis and having an edge adapted to engage the length of a blank in arcuately moving from a retracted position, across the track outlet to close the same and into said passage for engaging a blank and transferring the same through said passage from said location to the passage outlet whereby the blank axis disposition is changed angularly, guide means to direct a blank from the passage outlet to the jaw entrance, and means for returning the blade to retracted position opening the track outlet to permit a subsequent blank to enter said location.

9. A Work head as described in claim 8 wherein the clamp element of the axial clamping means is a plate formed with a blank head guide edge sloping inwardly toward the defined work station in the region between said blank passage outlet and the work station.

10. In a work head wherein a headed blank is radially and axially clamped at a work station between a fixed jaw and a movable jaw, a clamping structure comprising: a jaw mounting frame with a fixed jaw rigidly secured thereon, a pivoted arm carrying the movable jaw, the arm being spring biased toward the fixed jaw for yieldably retaining a blank between the jaws, and stop means for limiting the approach of the movable jaw to the fixed jaw to maintain a space therebetween; said jaws having the opposed faces including a flat surface on the fixed jaw and a V-notch on the movable jaw providing three line contacts and defining a work station for blanks of a range of shank diameters; said jaws having a plurality of parallel paired respective slots extending across the opposed faces through said notch and flat face providing pairs of coplanar axial blank head clamping reaction surfaces whereby a range of blank lengths may be handled by one set of jaws, each pair of slots also providing blank head radial clearance upon blank radial clamping whereby the radial clamping is effected on a blank shank; means for applying a positive axial clamping force on the head of a blank in said work station; and means for applying a positive radial clamping force to the movable jaw.

11. A work head for clamping individual round shank headed Work blanks at a work station for a work operation by a tool advanced along a path coincident with the clamped blank shank axis, comprising: a fixed jaw and a movable jaw shiftable toward and away from the fixed jaw, said jaws having mutually opposed faces defining therebetween said work station, and the movable jaw be ing yieldably biased toward the fixed jaw for releasably radially engaging a blank therein; means for applying positive radial and axial clamping force to a blank in said work station; a blank injection mechanism including an injector finger reciprocable from a retracted position outside of and spaced from the jaws into a space between said jaws in a blank injection stroke for engaging a blank shank and translating the same in a direction perpendicular to the shank axis into the work station; said jaws having opposed faces mutually formed with inlet bevels for camming the movable jaw away from the 16 fixed jaw upon injection of a blank into the work station, thereby releasing a preceding blank therefrom; said jaws being mounted for adjustment relative to said injector finger in the direction of tool advance, and said jaws having the opposed faces including a flat surface on the fixed jaw and a V-notch on the movable jaw providing three line contacts and defining a work station for blanks of a range of shank diameters; said jaws having a plurality of parallel paired respective slots extending in the direction of injector finger reciprocation across the opposed faces through said bevels, notch and flat face providing pairs of coplanar surfaces to support the underside of an axially clamped blank head, each pair of slots also providing blank head radial clearance upon blank injection and radial clamping whereby the said camming of the movable jaw and radial clamping are effected by a blank shank, whereby a range of blank lengths may be clamped therein with the blank head supporting surfaces at substantially the same position relative to the blank engaging portion of the injector finger.

12. A work head as described in claim 11 having a work coolant nozzle adapted to direct a coolant stream perpendicularly upon the shank of a blank at said inlet bevels of the jaws whereby shorter head-heavy blanks may be maintained with shanks on said inlet bevels for engagement by the injector finger.

13. A Work head as described in claim 11 wherein axial blank clamping is provided by a spring retracted blade positively advanced axially of a blank to bring a blade edge to bear on a blank head for clamping the same against a selected pair of said coplanar surfaces, said blade edge having a portion leading toward said work station for camming engagement with a blank head upon injection into said jaws.

14. In a work head wherein a blank having a round shank portion and a shouldered enlargement, such as a headed blank or the like, is to be radially or axially clamped at a work station between a fixed jaw and a movable jaw, a clamping structure comprising: a jaw mounting frame with a fixed jaw rigidly secured thereon, a second jaw mounted for movement toward and away from the fixed jaw and spring biased toward the fixed jaw for yieldably retaining a blank between the jaws; said jaws having the opposed faces including a fiat surface on one jaw and a V-notch on the other jaw providing three line-contacts and defining a work station for blanks of a range of shank diameters; said jaws having a plurality of parallel paired respective slots extending across the opposed faces through said notch and flat face providing pairs of coplanar axial clamping reaction surfaces for the shouldered enlargement whereby a range of blank lengths may be handled by one set of jaws, each pair of slots also providing radial clearance for the enlargement upon blank radial clamping whereby the radial clamping is effected on a blank shank; and means for applying an axial clamping force on a blank in said work station to hold the same against said reaction surfaces.

References Cited in the file of this patent UNITED STATES PATENTS 828,176 Bailey Aug. 7, 1906 1,395,659 Algrim Nov. 1, 1921 1,902,762 Conlon Mar. 21, 1933 2,646,708 Nickas July 28, 1953 2,811,876 Batchelder Nov. 5, 1957 

